Elevator.



G. JOHN.

ELEVATOR.

APPLICATION FILED Aus.1e.1912.

LlQlQGQ Patented June 8, 1915, Eng Ti 2; SHEETSSHEET1.

rgwzmma a THE NORRIS PETERS CO, PHDTG-L!THO.. WASHINGIUN. u. L,

G. JOHN.

ELEVATOR.

APPLICATION FILED AUG. 16, I912.

Patented June 8, 1915.

$3) 13 attozm a4.

(37 "v A W r B C V H1594 "w i THE NORRIS PETERS C0,. PHGTO-LITHCL, WASHINGTON. D. k

counterbalance to GRIFFITH JOHN, OF YONKERS, NEW YORK,

OF JERSEY CITY, N EW' JERSEY, A. CORPORATION nnnvaren covri nnv,

ASSIGNOR TO OTIS GE NEW JERSEY.

ELEVATOR.

1 fire-1,96%.

Application filed Augustin To aZZ 107mm it may concern Be it known that l, GRIFFITH Jenn, a subject of the King of Great Britain, residing in Yonkers, in the county of VVestchester and itate of New York, have invented a new and useful Improvement in Elevators, ofwhich the following is a specification.

lily invention relates to improved means for counteiweigliting an elevator, and its main object is to compensate for the variations in the extent of the cables on opposite sides of the overhead or guide sheaves.

In elevators it is common practice to a greater or less extent the weight of the car, cage, or platform and its directly attached parts by means of a counterweight connected with the car byv a cable or cables passing over suitable guide sheaves located at the top of the hatchway.

While it is possible exactly to counterbalance the car and its average load with a counterbalance weight for a certain given position of the car in the hatchway, there is not a perfect counterbalance for any otherposition of the car owing to the variations in the extent of the cables upon opposite sides of the overhead or guide sheaves, the greater portion of the cables acting in opposition to the counterweight when the car is at its lower limit of travel, while when the car is at the top of the hatchway the weight of the cables acts in conjunction with that of the counterbalance weight. In order that an elevator may operate efiiciently and at uniform speed throughout its entire travel, it has been found necessary to compensate for this varying weight of the cables and the usual method for efiecti'ng this result is to connect a chain or chains of the proper weight to the bottom of the car or counterweight, and to secure the opposite ends of said chain or chains to a fixed point in the hatchway midway between the top and bottom, or to connect the bottom of the car and counterweight by chains or ropes. While these arrangements are more or less satisfactory from a theoretical standpoint, there are certain practical objections thereto. F or instance, since the chain or'chains are supported only at their extreme ends, they are free to thresh about and become lrinlred, and at best are unsightly and extremely noisy. Furthermore, for certain positions of the car in the hatchway, the entire weight of the compensating chains Specification of Letters Patent.

Patented June a, 19115..

, 1912. Serial No. 715,314.

must be borne by the hoisting cables. That is to say, when the cables are connected to the bottom of the car and the latter is at the top of the hatcnway, the hoisting cables mustsupport the combined weights of the car and its lead, the counterweight, compensating chains and the hoisting cables themselves and when the elevator travels to a consideraole'heigl it is readily seen. that tl is combined weight may reach enormous proportions necessitating a large number of heavy powerful hoisting cables, the

cost of which cables alone amounts to considerable.

.My invention overcomes all of the above, as well as other objectionable features, in a simple, practical and efficient manner, and the same may best be understood by reference to the accompanying drawing, in wh1ch- Figure 1 represents in elevation an elevator containing an embodiment'of my in-' vention; Fig. 2 is a side elevation view of Fig. 1; Figs. 8 and 4- are side and front views, respectively, of a compensating chain;

Figs. 5 and 6 are front'and spectively, of a modification.

Referring to the drawing, a cage, car or platform; A. whatever may be its form or construction, is adapted to move up and down upon suitable guides arranged vertically within the hatchway B under the action of any suitable motive power such as an electric motor M which may be located at the top of the hatchway as shown in Fig. 1, or elsewhere if desired. A traction sheave T is carried upon the shaft of the motor and is grooved to receive one or more cables H which are fastened at one end to the can A and at the other end to an appropriate counterbalance weight WV. sprocket wheel S is carried upon the motorshaft and rotates with it. This sprocket wheel maybe of any desired size, but for purposes of illustration I have shown the same just one half the diameter of the traction driving sheave T. Asproclret chain G rear views, re-

is engaged by the sprocket wheel S and each end of this chain is secured :to another chain Cv which is substantially heavier than the chain C sate for thevariation in the H, the lighter chain C merely acting as driving and suspensory means for the chain C. The chain G is somewhat heavier than and whose function is to compen hoisting cables 7 'ing cable or ,aweight equal to a length oftwice the weight of the hoisting cables and substantially one half their length and travels at one half the speed due to the 2:1 ratio of the traction sheave wheel S. At the lower bightof the chains C and C I arrange a guide pulley P which is preferably held under a slight tension by means of a weighted frame F having a limited movement on the guides G secured to the side of the hatchway. The funetionof the pulley P is to guide thechains'C and G and overcome any tendency for them to sway as the car moves up and down in the hatchway. lhe sprocket'chain C may be of light construction, of sufficient strength to support the weight of the chain C, and the chain C may be of any desired character provided it has. the necessary weightv and strength, shown in Figs. 3 and an pivoted links and known as a block chain. A chain of this kind has no'lostimotion between such as is found in a welded link or jack chain, and will run without noise of any kind while at the same time possessing great strength in proportion to its weight. It will be noted that chain C per unit length should be more than twice the'weight of the same length of hoistcables in order to compensate for both the cables and the chain G, that is to-say, 'a foot length of chain C should have twice the weight of a foot the hoisting cable or cables plus the weight of a foot length of'the sprocket chain C.- With the weights thus proportioned the elevator system balance for all positions of the car with a given load. I

Inasmuch as the chains C and C are suspended from" the sprocket sheave "S carrie by the motor shaft, the hoisting cables are never called upon to support a load other han that of the car and its load; the hoist ingj ropes and the counterbalance weight.

This feature alone is of considerable 1111-:

. aortance in elevator practice, 'articularl' l r I combined weight weigh in excess'of 1500 lbs. using in thecase of a high rise tract on elevator.

For example, in a traction elevator having a rise of 200 ft. the hoisting cables Wlll of a" diameter. The usual method for compensating for the weight'of cables by hanging chains under the car would subject the hoisting cables to a load in excess of the of the car, counterbalance weight and weight'of the cables by approximately 1500 lbs. when the car is at the upper landing. My invention enables one to remove this load of 1500 lbs. from the hoisting cables and place'it where it should be, on the hoisting machine, thereby substantially in- Gepies of. this patent may be. obtained for five cents each, by addressing the i Washington, D. G.

and the sprocket will compensate, for

but is preferably constructed as, facility by merely proportioningthe the links the weight of the Will be in perfect simplicity of car, counterweight and means running at a speed less than that of the cables for counterbalancing the cables 'without increasing 6 cables creasing the factor of safety of the hoisting or suspensory cables which of course is most desirable.

Referring to in Figs. 5 and compensating length of the same speed as that of the car.

the modification as shown 6, it is there seen that the chain 0 extends the full hatchway and travelsat the In this instance the weight of a foot length ofchain G will equal the weight ofa foot length of hoisting cable or cables plus the weight of afoot lengthof chainC which arrangement of hoisting cables for all positions of the car.

I have shown a. 2:1 and 1:1 ratio of travel of the hoisting cables and compensating chain, but it will be understood that other ratios maybe employed withequal eter of the sprocket wheel S and weight of 1 chain C to suit the new conditions.

Vl hile l have shown and described the compensating device as a chain this term should be considered the form ofa series of connected weightsor links of which a chain is but one example may be used. 7 I y it will be observed thatthe sprocket wheel 3 may be located at any position uponthe shaft of the motor, so as to bring the com-. pensating chain inclose to the'side of the hatchway out of the way, or if desired the shaft may be lengthened another shaft having the sprocket wheel thereon, V entirely outside of the hatchway in some other suitable or desirable place.

Y My invention is herein shown as embodied in. a direct drive or traction elevator for illustration, and while the invention is particularly adapted toelevators of this character it is also adapted to elevators or other hoists of all descriptions.

What I claim is 1. In an elevator,-

' and connecting cables,

the tension thereon.

' 2. In an elevator, car, counterweight and means running at 'a speed less than that of the car for counterbalancing the said the variation of weight di amy or connected to so that the cham can be located he combination of a the combination of a and connecting cables,

in its broadest sense, since any arrangement of flexible weights in cables without increasing the tension thereon.

In testimony whereof, I have signed my name to this specification in the presence of two subscribing witnesses. I

.GRIFF 1TH JOHN.

Witnesses:

D. L. HoLBRooK, G. BLINN.

Commissionerof Patents, 

